Port-Channel Question

[oscar.aguilar]

I need help on a cisco config and was wondering if anyone could help me. I currently have 4 Cisco 3750 which are stacked in our server room and now I have 4 more Cisco 3750 which are stacked also in a wiring closet. I just up-linked both 3750 stacks using 4 Fiber SFP SX modules. I wanted to config a port-channel on each stack however after 5 minutes or so the switch disables the port-channel interface as a config error on the port channel.

This is my current config

interface Port-channel1

description "Uplink to 3750 Stack 2"

switchport trunk encapsulation dot1q

switchport trunk native vlan 7

switchport mode trunk

!

interface GigabitEthernet1/0/25

switchport trunk encapsulation dot1q

switchport trunk native vlan 7

switchport mode trunk

channel-group 1 mode on

**Update** Just as FYI we have a VoIP network in which I'm trying to do is load balance/agrigate the network traffic a cross each switch in the stack (Cross Stack EtherChannel).

Thanks for the help.

[vladrac-ccna]

Is this the configuration for both side? I guess you have the other gigas with the same configurations?

vlad

[d-garnett]

what is the error message that it gives you?

also if you could produce:

show etherchannel summary

show etherchannel detail

show etherchannel port

.....and sw version

it may help

[oscar.aguilar]

Attached are the config for our first 3750 Stack and sh of the int.

[oscar.aguilar]

Here is the config and sh int for the seond stack.

[rich]

This is just a guess but . . .

Try adding a switchport command to each interface.

For example:

interface GigabitEthernet4/0/1

switchport mode trunk

channel-group 1 mode on

[rta.presidio]

You should make all the interface configs similar. If you have on the port-channel:

switchport access vlan 7

switchport mode access

then on all the physical interfaces, you should have

switchport access vlan 7

switchport mode access

channel-group 1

[vladrac-ccna]

Hello Oscar,

sorry for the delay.

But presidio's post gives you the answer.

You can check this configuration on the following link:

http://www.cisco.com/en/US/products/hw/switches/ps5023/products_configuration_guide_chapter09186a00801cdea1.html#1033981

Switch# configure terminal

Switch(config)# interface range gigabitethernet1/0/25 - 26

Switch(config-if-range)# switchport mode access

Switch(config-if-range)# switchport access vlan 7

Switch(config-if-range)# channel-group 1 mode on

Switch(config-if-range)# end

do the same for all physical interfaces configured in the channel-group

Lets us know if it helped.

Vlad

[nethelper]

Hello,

try and configure:

no errdisable detect cause gbic-invalid

globally on your switches. Also, try and set the channel mode to 'desirable' rather than to 'on'.

Regards,

Nethelper